One moment my sweetheart is sound asleep; the next, she is on her feet, blankets flung to the floor.

What just happened? It’s what she’s wondering, and you might be, too. Bad dream? Home invasion? Microburst?

In a way it’s all of those things combined: A dog has invaded a home claimed by cats and it’s blowing up into a nightmare.

I’m awake but in another room when this tempest — I don’t think it’s an accident that the word, rearranged, spells ‘pets met’ — breaks out, so can’t say for sure who started it.

What I do know is there is a lot of scrabbling noise and a lot of objects being tossed around at the other end of my pad. I hustle down the hallway to find a TV remote on the floor, along with books, my computer mouse and approximately $7 worth of quarters that were previously stacked neatly inside a paper tube.

I can’t see any animals at all. But that’s only because they have all made their way into a small storage area to continue their skirmish amid a set of winter tires and two pairs of snowshoes.

I’d call it a game of cat and mouse if it weren’t a game of cats and dog, and not really a game at all. This situation, I realize, could easily result in injury — to the eye of the dog, or the neck of a cat. One of the cats — it strikes me with a gut-hollowing panic — could even die.

It’s time to call in the experts.

Ashley Rozon, an animal behaviourist with Bark Busters, arrives on a sunny afternoon bearing a small plastic water bottle and a couple of jangly beanbags — tools I can use to get the dog’s attention if he’s about to charge after a cat.

Ultimately I will end up using the spray bottle more on my cat Vinny — Rozon, who visits me twice in my home, takes to calling him Mr. V. and characterizing his general demeanour as “I’m Mr. Man” — but during this first session the focus is on getting Joe, the newcomer to the household, to respect the rules and recognize that the three felines, two of which belong to my girlfriend, are not prey.

“If he gets perked up, you have to calm him down,” Rozon says. “If he’s adrenalized, with his tail up and chest out, the chance of him going after the cats is much higher.”

Rozon recommends using one consistent, guttural noise — a “bah” sound or “hey” — along with a clap of the hands to “redirect him” and let him know “he’s making a wrong choice.”

The goal, she says, is to nip any potential conflict in the bud.

This begins with discouraging the dog from staring at a cat, as Joe is very much inclined to do. “When he’s locked in like that, you redirect his thinking,” says Rozon.

I try her technique and “bah” at the dog. My version is more like a huff, or a “hah,” but it seems to work. He gazes down, and away, and licks his lips.

You could say I’ve put him in his place but Rozon prefers to avoid terms like dominance and submission. “I would say you are providing leadership, and he is being calm and respecting your wishes,” she says.

Rescue mutt Joe takes a break from competing with cats, while Alister the amiable tabby looks on from his basket.Jim Moodie/Sudbury Star

When the animals are all in the same space I have to be vigilant and lay down the law — even set up some situations that deliberately tempt and test the dog, in order to pre-empt and correct the behaviour — but it’s also important to separate this furry menagerie and give the dog “a safe space” where he can chill on his own.

That could be a crate, if I was crate-training, but since I’m not Rozon says it’s fine to simply put him in the bedroom and close the door.

All dogs have some prey drive, says Rozon, although some breeds have more than others. Huskies, for instance, “have a prey drive and a half.”

Joe is half lab, which accounts for his congenial side, but he’s also got some husky in him and, I’m convinced, pit bull. This may explain why half of him seems to view the cats as things to ogle and possibly eat.

Cats have their own characters, too, and a stubborn alpha like my own Mr. V. can make the compatibility challenge that much harder.

But whatever breeds and personalities you are dealing with, the key with dog-cat harmony is to introduce them gradually and establish boundaries well before a ruckus breaks out.

“The biggest mistake people make is to just shove a new animal in the house with other animals,” says Tammy St. Louis, a dog trainer based in Garson. “People tend to go in all heart when they get a pet, without any rules, so it’s like ‘Welcome to our house, do whatever you want to do.’ And that’s a recipe for disaster.”

St. Louis has juggled a few different cat-dog combos over the years, some trickier than others. In one case, she took in a husky that “had killed a bunch of cats before we got her,” but even this dog eventually learned to live with the resident feline.

“That dog had to wear a muzzle for a while, and the cat had a gate it could jump over and a tall cat tree it could scurry up,” she says. “Every room had an escape route.”

Joe isn’t sure what to make of George, a fearless cat who is a member of dog behaviourist Ashley Rozon’s household. The two quickly hit it off, however, largely because George is so relaxed and doesn’t challenge or flee from the dog.Jim Moodie/Sudbury Star

It takes patience and commitment, but you can make even the most unlikely matches work if you monitor body language closely and are quick to correct problematic behaviour, according to St. Louis.

“A lot of people are not paying attention and not seeing the signs,” she says. “If the dog is following the cat too much, even though it might look harmless, that’s a problem, too.”

St. Louis is an advocate of crate-training and her general approach when mixing cats and dogs is to “crate and rotate” for the first few weeks — keep the dog confined and let the cat roam around, and vice versa — until they get used to each other’s presence.

“If the dog will sit in the cage and be quiet when the cat walks by, then you can start to let it out, but if it’s acting like a fool, you want to keep him in there.”

Baby gates can work well too, in her experience, as a way to separate pets while still allowing them to smell and acclimatize to one another.

But the main thing is you have to provide the animals with direction, as well as reassurance. “They need to know that the adults have control of the situation,” she says.

St. Louis cites the example of Havoc, a Belgian Malinois she acquired a couple years ago.

“He had lived with a couple cats before, but when he came here he wanted to kill my cat,” she says. “I had to put a ton of rules on him for a long time about her. And she had to know that I’m going to make her safe.”

Cats may require discipline too, for the sake of the dog. “You have to show the dog that you have control of the cat,” notes St. Louis.

The dog and cat I seem to have chosen (or who chose me, it’s not quite clear) each bring their own stubborn traits to the table — Joe being hardwired to chase smaller mammals; Mr. V. being a badass who doesn’t back down easily — so my efforts at discipline and diplomacy have to be doled out in equal measure.

But after a rough start, during which I wish I had been far more proactive, it’s finally starting to work out.

As I type this, my sweetheart is sleeping peacefully with Joe on the floor beside her and both her cats curled up on her legs.

Mr. V. may not be on the bed, much less on the floor spooning with Joe, but he’s not hiding in the tire closet either, and he’s not arching his back and emitting a bloodcurdling yowl.

In a nutshell, there is no major mayhem breaking out.

That’s a testament, I think, to the adaptability and intelligence of animals, but it has also involved a lot of belated effort on my part, with helpful input from the pros.

I was lucky in the past to have dogs and cats that just magically got along, and naively thought that would happen again.

What I’ve learned is you have a role as a pet owner to manage these situations, and it’s only fair to the animals you have in your midst to do so.

Leaving the animals to work it out themselves may sound like a liberal, fuzzy idea, but it’s really a lazy course of action, and a potentially disastrous one.

As St. Louis puts it: “Letting nature take its course — not a good plan.”